This is a full theme. I themed just about everything that it is possible to theme (there is a lot more than what is shown in the screenshots).
The homescreen is not Today or Zen, it is both. If you are not on Messages or Calendar you just get the Zen style view, but as soon as you scroll over Messages Or Calendar you see your 6 new messages or 6 upcoming appointments.
*Click on the pics below to see them fullsize.
Download link and all the newer themes are at my new site The Theme Zone